'Eisen' was the German airborne operation by part of Hauptmann Walter Koch’s Fallschirmjäger-Sturmabteilung 'Koch' of Generalleutnant Kurt Student’s 7th Fliegerdivision and Generalleutnant Hans Graf von Sponeck’s 22nd Luftlande-Division to take and hold the bridge at Kanne in Belgium during the first day of 'Sichelschnitt' (10 May 1940).
One of a series of four related undertakings with 'Beton', 'Granit' and 'Stahl', 'Eisen' was undertaken by Leutnant Martin Schächter’s detachment of 92 men in 10 DFS 230A assault gliders, all but one of which landed next to their objective: as a result of a navigation error by the pilot of its Junkers Ju 52/3m tug, this last was released in the wrong area. The other nine gliders were towed through heavy anti-aircraft fire and released at 05.35, but as they began to descend toward their objective, the bridge was destroyed by several explosions as the Belgian garrison set off the demolition charges.
Unlike the garrisons of the other two bridges which the German airborne forces took on this decisive morning of the German offensive against the western powers, the Belgian defenders at Kanne had been forewarned by the fact the German mechanised column heading for the bridge to reinforce the 'Eisen' force was some 20 minutes ahead of schedule, its appearance ruining any chance of a surprise assault and giving the defenders sufficient time to destroy the bridge.
As the gliders came in to land, one was hit by anti-aircraft fire and crashed into the ground, killing most of the occupants, but the remaining eight landed successfully, the airborne troops storming the Belgian positions and eliminating the defenders. By 05.50 the airborne troops had secured the area, as well as the nearby village of Kanne, but were then subjected to a strong Belgian counterattack which was only repulsed with the aid of air support from Junkers Ju 87 Stuka dive-bombers. Several more counterattacks were launched during the night, and this meant that the airborne troops could not be relieved until the morning of 11 May. The 'Eisen' force suffered the heaviest casualties of all three assault groups ('Beton', 'Eisen' and 'Stahl') assigned to capture the bridges, with 22 dead and 26 wounded.